Assessment of the effectiveness of binder fatigue, rheology and chemistry parameters in evaluating cracking resistance in high RAP mixtures modified with recycling agents

The utilization of Reclaimed Asphalt Pavement (RAP) in pavement construction has gained prominence as a sustainable approach to reduce material costs and environmental effect. However, a significant challenge associated with increased RAP incorporation lies in the potential fracture distress caused by the aged binder. The purpose of this study is to assess the cracking performance of asphalt mixtures incorporating three levels of recycled materials (30% RAP, 50% RAP, and 30% RAP along with 5% Reclaimed Asphalt Shingles (RAS)). Three softening oils were employed to improve the cracking performances at two aging levels. Performance evaluations, including cracking performance assessments at intermediate and low temperatures, were carried out and compared with control mixtures. The findings of this study reveal that the incorporation of softening oils, as investigated herein, offers a viable means of producing asphalt mixtures featuring high RAP content while preserving performance comparable to that of a virgin mix. From a binder perspective, the Glover–Rowe (G–R) parameter and fatigue life at 10% strain level emerge as robust indicators for evaluating cracking resistance under conditions pertaining to intermediate and low temperatures.